Collax Groupware Suite is a complete collaboration, e-mail, and messaging server with Outlook MAPI support. It offers enterprise email server functions, anti-spam and anti-virus filters, GUI management, a file server for SMB, NFS, FTP, and Apple shares, backup/restore server, IM server, and fax and SMS server. The groupware offers AJAX Web mail, calendar, team calendar, contacts, and tasks, and supports ActiveSync for mobile devices. It is free for private or commercial use of up to five users.
Collax Business Server is an all-in-one Linux server for small- and medium-sized businesses. It delivers all the important network services within a heterogeneous business environment for communication, infrastructure, compliance, groupware, and storage, all in a reliable and secure way which is easy to manage. It also provides essential security functions such as firewalling and virus and spam filtering, to protect against hacker attacks, viruses, and unsolicited email messages.
zmaildrop is a mail delivery agent (MDA) specifically designed to analyze emails, extract relevant information, and send it to a Zabbix server. It is designed for use with schedulers, backup tools, and security monitoring tools that report information via email. As an MDA, it integrates easily with mail transfer agents (MTA) such as Postfix, Exim, and Qmail, or mail retrieving tools as Fetchmail. It is highly configurable, using a simple YAML syntax to describe tool-specific mail formats.
FuzzyOcr is a plugin for SpamAssassin that can be used on image spam. It supports optical character recognition using different engines and settings, a fuzzy word matching algorithm applied to OCR results, an image hashing system to learn the unique properties of known spam images, dimension, size, and integrity checking of images, and content-type verification for the containing email message.
Synspam uses Netfilter NFQUEUE to catch the source IP address of any machine connecting to your mail server, running multiple tests against it (RBL check, regexp on the reverse name, etc.) before forwarding the connection to the MTA. In order to have as few false positives as possible, a scoring system is used. If the source IP address is believed to be a spammer IP address, the connection can be dropped. There is a dry run mode if you just want to test it, which is the default.
CGI::ContactForm is a Perl module that generates a contact form for the Web and sends a message to a predestinated recipient. Unlike many form-to-mail programs, it's limited to this single purpose, but it allows you to set up a decently designed form with a minimum of effort. In other words, it's simple to use rather than flexible, even if there are quite a few customization possibilities.
Xuheki is a fully featured email (IMAP) client for the Web. It looks and feels like an application rather than a Web site. It is fast, clean, and features no page reloads. It supports multiple users per installment, multiple IMAP servers per user, and multiple folders per IMAP server. It also supports text or HTML email, attachments, inline images, printing, and more. It has an "AJAX" interface that could compete with desktop-based mail user agents.
Cyrus2Dovecot is a full-featured command line tool for converting the email messages of one or more users from the Cyrus format to Dovecot Maildir++ folders. It allows you to perform a server transition which is fully transparent to both POP and IMAP users, as virtually all available metadata is preserved during the conversion. This includes message UIDs, INTERNALDATEs, IMAP folder subscriptions, the UIDVALIDITY and UIDNEXT values for each folder, as well as all IMAP flags (including the first 26 user-defined keywords).
maildirquotad is used in conjunction with exim. Exim has no builtin facility for checking the quotas of a mailbox at RCPT TO time. And when you have many MX servers and only one mail hub that stores mail data, it became a real problem, for example, if an MX server has received mail but the mailhub defers it because recipient's mailbox is full, despite the fact that the MX server already has said to remote server that mail had been successfully delivered.